The present invention relates to improved shirred or sheated strands of tubular food casings and methods of manufacture. More particularly, the present invention relates to sausage or meat casings having improved end-dressings which substantially reduce or eliminate filling equipment jamming due to interference by residual casing material or loose tab-ends.
Food casings, such as those made of regenerated cellulose and collagen have been widely used for a number of years in processing frankfurters, sausages, bologna, etc. For instance, the basic process for manufacturing small diameter casings of regenerated cellulose is known as the "viscose process" and is described in such patents as U.S. Pat Nos. 2,999,756 and 3,835,113. Essentially, viscose is extruded through an annular die into a coagulating bath to form a tubular casing. The regenerated gel is impregnated with a plasticizer, dried and wound into flat reelstock. For convenience in handling and in filling such food casings, they are shirred on high-speed shirring machines, like those described in U.S. Pat. Nos. 2,010,626; 2,583,654; 2,722,714; 2,722,715; 2,723,201; and 3,451,827. In the shirring process, lengths of from 40 to 200 feet of casing are compacted into pleated strands of a few inches, e.g., 4-30 inches at a rate of 10 to 15 ft./sec.
As part of the shirring process, the strands must be severed, for example, from continuous reelstock from which they originated. Most of the methods for severing shirred artificial sausage casings routinely result in the formation of a loose or unshirred tab-like piece of residual casing material which remains at the horn insertion (tab) end of the strand. In the case of manual filling of sausage casings, the presence of such a loose tab at the horn insertion end can be rectified by the operator's manual dexterity and does not present a major problem. However, in high-speed, highly automated filling operations, the presence of a loose tab-end on the horn insertion end of a strand can have more major consequences. For example, a loose tab-end can interfere with the proper fitting of a strand onto the stuffing horn of a high-speed filling machine becoming entangled as the horn is inserted automatically into the strand. Under such circumstances, the strand can deshirr from both the filling and horn insertion end causing the process to jam, discharging meat into the filling station work area which means lost meat emulsion, as well as lost production output due to downtime. Accordingly, there is a need for improved tubular strands of food casings and methods of manufacture wherein the casings have end-dressings which eliminate jamming and fouling when used in conjunction with high-speed automated filling equipment.
The present invention provides for more dependable end-dressed sausage/meat casings through the elimination of interfering residual casing material or loose tab-ends formed as by-products of shirring operations. By ironing down the tab-ends formed on at least one end of a severed shirred casing by application of heat to the terminal edge of the side-walls of a strand under controlled temperatures, the loose tab will cling and become an integral part of the casing side-wall. But, because the tab and adjacent casing pleats are not fused by the ironing process the casing will completely deshirr in a normal manner during filling operations as meat emulsion is forced into the strand thereby avoiding loss or waste of casing material.
Accordingly, it is a principal object of the present invention to provide more dependable, fail-safe strands of tubular food casings which are compatible for use on high-speed automated filling equipment.
It is a further object of the present invention to provide a method for making improved end-dressings on artificial sausage casings.
These and other objects, features and advantages of the present invention will become more apparent from the following more detailed descriptions.